Patent GB-804121-A (GB)
Title: Improvements in or relating to alkyl phenols
Inventor: PARC GUY
IPC: C07C37/14
Filed: 1956-04-06
Abstract: Natural and synthetic lubricating-oil compositions, petrol obtained by cracking or reforming processes, jet fuels, paraffin and petroleum jelly contain as antioxidants alkyl phenols of the general formula <FORM:0804121/III/1> wherein R1 is a primary, secondary or tertiary alkyl group having from 1 to 5 carbon atoms, R2 is a methyl or ethyl group and R3 is a cyclohexyl group, e.g. 2,4-dimethyl-, 2-tert.-butyl-4-methyl - and 2 - tert. - amyl - 4 - methyl - 6-hexyl phenols (see Group IV (b)).ALSO:Natural rubber compositions comprise as antioxidants alkyl phenols of the general formula <FORM:0804121/IV (a)/1> wherein R1 is a primary, secondary or tertiary alkyl group having from 1 to 5 carbon atoms, R2 is a methyl or ethyl group and R3 is a cyclohexyl group, e.g. 2,4-dimethyl-6-cyclohexylphenol, 2-tertiary-butyl-4-methyl-6-cyclohexylphenol and 2-tertiary-amyl-4-methyl-6-cyclohexyl phenol (see Group IV (b)).ALSO:The invention comprises alkyl phenols of the general formula <FORM:0804121/IV (b)/1> wherein R1 is a primary, secondary or tertiary alkyl group having from 1 to 5 carbon atoms, R2 is a methyl or ethyl group and R2 is a cyclohexyl group and processes for the preparation thereof which comprise (a) reacting a dialkyl phenol of the general formula <FORM:0804121/IV (b)/2> where R1 and R2 have the meanings specified above with cyclohexene in a homogeneous liquid phase in the presence of a soluble alkylation catalyst at a temperature of from 50 DEG  to 200 DEG  C., and (b) reacting a monoalkyl phenol of the general formula <FORM:0804121/IV (b)/3> wherein R2 has the meaning specified above with cyclohexene in a homogeneous liquid phase in the presence of a soluble alkylation catalyst at a temperature of from 50 DEG  to 200 DEG  C. and then reacting the resulting cyclohexyl-alkyl phenol with an aliphatic olefine containing from 2 to 5 carbon atoms in the presence of an alkylation catalyst which is soluble in the liquid phase of the reaction mixture at a temperature of from 30 DEG  to 120 DEG  C. and a pressure of from 1 to 30 atmospheres.  Olefinic starting materials specified include isobutene, methyl-2-butene, propylene, butenes-1 and 2.  Alkylation catalysts mentioned include sulphuric acid, oleum, boron trifluoride and complexes thereof and Friedel-Crafts catalysts such as aluminium chloride.  In examples: 2,4-dimethyl-6-cyclohexyl-phenol is prepared by reacting 2, 4-xylenol with cyclohexene in the presence of boron trifluoride (1); 2-t-butyl-4-methyl-6-cyclohexyl-phenol is prepared by reacting cyclohexene with p-cresol in the presence of boron trifluoride, distilling off the 2-cyclohexyl-4-methyl-phenol obtained and reacting the latter with isobutene in the presence of concentrated sulphuric acid (2); and 2-t-amyl-4-methyl-6-cyclohexylphenol is similarly prepared using methyl-2-butene-2 in the second stage (3).  The products of the invention are employed as antioxidants, e.g. in unsaturated hydrocarbons, petrol, jet fuels, insulating oil, turbine oil, natural and synthetic lubricating oils and rubbers, paraffin, petroleum jelly, grease, wax, aldehydes, monoacid esters of polyhydric alcohols or polyacid-polyhydric mono- and polyesters.